ELECTRIC 'FALL.' 171 



nected with the multiplier at two points in its length, 

 in this case also a part of the current must, in ac- 

 cordance with the law of the distribution of currents, 

 branch off through the multiplier. 



8. This may be made intelligible in another way. 

 We saw that a certain electric tension exists at the poles 

 of an open apparatus, and that the opposed tensions 

 of the two poles are the causes of the current in the 

 closing wire. If the poles were but once charged with 

 proper quantities of electricity, these would unite in 

 the wire, with the result of producing an instantaneous 

 current. But as, in consequence of the electromotive 

 force of the apparatus, the tension at the poles is con- 

 tinually renewed, the current is continuous. So that at 

 both ends of a closing wire opposed tensions prevail con- 

 stantly, and these act on the natural electricity present 

 in the wire, as in every other body, and set it in motion. 

 Consequently, while the current flows through the wire, 

 different tensions must prevail at the various points of 

 the wire. At the point of contact with the positive 

 pole there is a definite positive tension ; at the point 

 of contact with the negative pole there is a similar 

 negative tension, and in the middle of the wire there 

 must be a point at which the tension = 0. This may 

 be diagrammatically shown by representing the tension 

 which prevails at each point of the wire by a line de- 

 scribed at right angles to the wire, the length of which 

 represents the tension proper to the point in case. Let 

 a b (fig. 41) be the wire ; then the line a c is the ex- 

 pression of the tension existing at one of its ends, 

 which is connected with the positive pole. In order 

 to indicate that the tension at the other end, 6, is 

 negative, i e. of an opposite kind, let the line b d be 



